$ touch ¿
$ ls ? > zz
$ xxd zz
00000000: c2bf 0a

$ echo '¿' > yy
$ xxd yy
00000000: c2bf 0a  

$ touch xx
$ rename -v 's/xx/¿/;' xx
xx not renamed: ¿ already exists
$ rename --version
/usr/bin/rename using File::Rename version 1.13, File::Rename::Options version 1.10

##</code><code>##

$ perl -e 'use utf8; print "¿\n"' > ww
$ xxd ww
00000000: bf0a

$ perl -e 'use utf8; $c="¿\n"; utf8::upgrade($c); print $c' > vv
$ xxd vv
00000000: bf0a

##</code><code>##

$ perl -e 'print "¿\n"' > uu
$ xxd uu
00000000: c2bf 0a 

$ curl --silent --head 'http://localhost/' | grep 'Content-Type'
Content-Type: text/html; charset=utf-8